This invention relates to an image processor.
Transmissions via communications lines in video conference and in video telephone are slow, and transmission of a tremendous volume of image data requires the process of encoding. ITU-T (International Telecommunication Union--Telecommunication Standardization Sector) Recommendations H.261 and H.263 are known as adoptable encoding methods. These recommendations specify CIF (Common Intermediate Format) and QCIF (Quarter CIF). Whereas a CIF picture is composed of 352.times.288 pixels, a QCIF picture is composed of 176.times.144 pixels. The use of BCH (Bose-Chaudhuri-Hocquenghem Code) error correcting codes in sending and receiving encoded data is also specified in these recommendations. In addition, other encoding methods named after the experts groups of ISO (International Organization for Standardization) have been known, and these encoding methods are JPEG (Joint Photographic Coding Experts Group) which is the international standard for color non-moving picture compression and MPEG (Moving Picture Experts Group) which is the international standard for multimedia moving picture compression.
Encoded data, produced by the process of encoding, are converted into analog video signals by the process of decoding. Conventionally, encoders for image encoding have been prepared independently of decoders for image decoding.
Because of such separate preparation, the design cost increases twofold, therefore increasing the cost of image processing systems. Another problem is that it becomes impossible to make an image processor adaptable to a large number of applications.